21250561565615 has 8 divisors (see below), whose sum is σ = 25748253237408. Its totient is φ = 16835396346720.

The previous prime is 21250561565587. The next prime is 21250561565663. The reversal of 21250561565615 is 51656516505212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21250561565615 - 2²² = 21250557371311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20631612656 + ... + 20631613685.

It is an arithmetic number, because the mean of its divisors is an integer number (3218531654676).

Almost surely, 2^{21250561565615} is an apocalyptic number.

21250561565615 is a deficient number, since it is larger than the sum of its proper divisors (4497691671793).

21250561565615 is a wasteful number, since it uses less digits than its factorization.

21250561565615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41263226449.

The product of its (nonzero) digits is 2700000, while the sum is 50.

The spelling of 21250561565615 in words is "twenty-one trillion, two hundred fifty billion, five hundred sixty-one million, five hundred sixty-five thousand, six hundred fifteen".